From Barrea town center, head for Alfedena taking SS.83 up to km 67.
When you reach a hairpin bend, on the right, follow a carriage road for about 700m until you reach a detour on the left to the trail marker K4 crossing the beech wood of Valle dell'Inferno and, constantly climbing, you will cross the moraine of an ancient glacier. In 40 minutes you will get to Valico del Buon Passo, with an image of Madonna delle Grazie protecting the travelers. Shortly after, you will get to the highest point of the itinerary (1,656m) and then go down into the wonderful basin where the enchanting Lago Vivo is set at 1,591m, dominated by the summits of Iamiccio, Tartaro, Altare, and Petroso. The latter, with its 2,249m, represents the highest summit of the Park.